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AbstractKeywords1. Introduction2. Mathematical description3. Numerical algorithm4. Specification of the problem and boundary conditions5. Results and discussions6. ConclusionNomenclatureShare and CiteRelated Articles
Article Open Access1 January 2026

Computation of compressible non-isothermal power-law model developed Taylor-Galerkin Pressure-corre

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Anas Al-Haboobi1, and Samah H. Al-Zaidi1

1University of Kufa

Journal of Thermal Engineering 2026, Vol. 12, Issue 4, pp. 1337-1349; doi.org/10.47481/jten.0033

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Abstract

In this study, a modified Taylor-Galerkin/pressure-correction finite-element approach has been developed to analyze non-isothermal, compressible, non-Newtonian, and inelastic fluid flows. In many cases, the coupling of viscosity and density to pressure and temperature is critical for accurate simulation of complex industrial and natural flows. The governing equations include the compressible Navier-Stokes system, the viscosity power-law model (for fluid rheology), and the Tait equation of state (to relate pressure and density). This important development is based on the integration of a two-step Lax-Wendroff method into the energy equation solver, enabling accurate thermal coupling and ensuring numerical stability. The novelty of this work lies in being the first to integrate compressibility, non-Newtonian viscosity, and non-isothermal effects into the Taylor-Galerkin/pressure-correction framework developed for power-law fluids. This integrated approach allows the simulation of high-fidelity, strongly coupled flow cases that are intractable for standard solvers. This provides a robust, approximate, and generalized method for higher-order problems in fluid mechanics, applicable to engineering or geophysical environments. The method’s performance is assessed by investigating the influence of the power-law index, the consistency coefficient, the Prandtl number, and the thermal conductivity on the flow variables. The results show that, for a shear-thickening fluid, increasing the power-law index from 0.5 to 1.5 reduces the outlet velocity by 10%; by contrast, increasing the consistency coefficient from 1 (base case) to 20 raises the outlet velocity by up to 35% in both shear-thinning and shear-thickening scenarios. The centerline pressure increases with the consistency coefficient, and the density shows a similar trend. Thermal analysis indicates 22% increase in wall temperature under conditions of low thermal conductivity when the Prandtl number decreases from 1.4 to 0.6; however, the wall temperature increases rapidly in compressible, shear-thickening flows. Shear and normal stresses, which are elevated relative to those in a Newtonian fluid, can increase substantially (by 50%) as the power-law index and the consistency coefficient increase, indicating strong nonlinear rheological effects.

Keywords: Compressible flow; developed taylor-galerkin/pressure-correction method; non-isothermal flow; non-newtonian; power-law model

1. Introduction

Non-Newtonian fluids constitute an important class in fluid dynamics, with relevance spanning theoretical understanding and practical applications across multiple industries. The non-constant viscosity of these materials, which includes sauces, blood and polymeric solutions is responsible for flow behaviors that are drastically more complex than the behavior of Newtonian fluids [1-4]. Such complexity is particularly relevant to engineering, biomedical, and environmental fields, which can benefit from more accurate representations of flu-

id dynamics and thereby improve their design processes and operational performance. Thus, the study of non-Newtonian fluids remains an area of considerable research interest. As another example, [5,6] investigate atomization processes for non-Newtonian fluids and [7–10] consider the gas bubbles behaviors within a non-Newtonian liquid matrix. In recent years, there has been growing scholarly interest in the study of Casson fluids. The Casson fluid belongs to a class of non-Newtonian fluids with generalized Newtonian behavior usually associated with the presence of a yield stress, and in recent times it has received increased attention from scholars due to its particular

Corresponding Author E-mail Adress: anasm.ali@uokufa.edu.iq *

Submitted: 17 February 2025 ; Accepted: 31 May 2025 This paper was recommended for publication in revised form by Editor-in-Chief Ahmet Selim Dalkılıç Published by Yıldız Technical University, İstanbul, Türkiye This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

relevance for many biomedical and industrial applications (cf., e.g., [11-20]).

the power-law model for non-Newtonian fluids, has not yet been examined.

The behavior of non-isothermal, non-Newtonian fluids play a pivotal role in a wide range of industrial and engineering applications, such as polymer processing, geothermal flows, food manufacturing, and biomedical systems. In these contexts, the interaction between momentum and thermal transport mechanisms is strongly influenced by the fluid’s rheological properties, particularly when nonlinear viscosity effects are present. While significant research has been conducted on the heat transfer characteristics of such fluids, especially through numerical modeling [21-26], most existing work assumes isothermal or incompressible flow conditions, which simplifies the thermodynamic and constitutive complexities of real systems. One of the most successful, widely applied, and accurate numerical solution methods for these important fluid problems, namely Taylor-Galerkin/Pressure-Correction (TG/PC) is primarily limited to the finite element method (FEM). This approach, introduced by Townsend and Webster [27], has been extensively used to solve a variety of fluid-related problems, primarily at isothermal conditions. For examples of such research, Tamaddon‐Jahromi, et. al, [28] used Taylor–Galerkin algorithms for solving model convection–diffusion problems for simulating more complex non-Newtonian flows. Carew, et. al, are solved a viscoelastic flow using TG/ PC method that incorporates consistent Petrov-Galerkin streamline upwinding within the discretisation of the constitutive equations [29]. A semi-implicit TG/PC was developed to investigate problems that manifest free surfaces associated with the incompressible Newtonian fluids by Ngamaramvaranggul and Webster [30]. [31] TG/ PC method was used for solving die-swell flow for viscoelastic and viscoelastoplastic fluids by Al-Muslimawi. Sharhan and Al-Muslimawi [32] had examine the flow of inelastic fluids with various shear properties by TG/PC algorithm. Al-Haboobi, et. al used TG/PC for first time to study a Newtonian isothermal flow around bluff body for incompressible [33] and compressible fluid [34].

The current work is based on this framework, but extends the earlier works by providing, for the first time, a generalized extension of the DTG/PC method to model non-isothermal, compressible, inelastic fluids governed by an Ostwald-de Waele power-law fluid law [36]. This model is able to capture both shear-thinning and shear-thickening behavior by varying the power-law index (n) and consistency coefficient (m). With the Tait equation accounting for compressibility and the energy equation allowing for thermal coupling, a fully coupled, thermodynamically consistent model is achieved.

A major limitation in the open literature is the lack of high-fidelity numerical methods capable of simulating compressible, non-isothermal, non-Newtonian fluids, particularly those described by the power-law model. Existing studies have primarily addressed either incompressible non-Newtonian flows or compressible Newtonian flows. Challenges arise from the nonlinear coupling among temperature, viscosity, pressure, and density, and from the need to simultaneously solve the energy equation and a pressure-density relation, such as the Tait equation of state.

To fill this research gap, Al-Haboobi and Al-Muslimawi proposed in 2023 a new method for non-isothermal compressible Newtonian fluids, namely the developed Taylor-Galerkin/Pressure-Correction (DTG/PC) method [35]. It solves the energy equation using a twostep Lax-Wendroff scheme and applies a pressure correction for compressibility based on the Tait equation of state. Its application to more complex constitutive laws, specifically those described by

To validate the robustness of the proposed methodology, we conducted a detailed numerical investigation in an axisymmetric cylindrical channel. The effects of key physical parameters (n), (m), (k), Pr namely the power-law index, the consistency parameter, the thermal conductivity, and the Prandtl number on important flow variables (axial velocity (v), pressure (p), density (ρ), temperature (T), shear stress ( x rz ), and normal stress ( x zz ) are analyzed. The originality of this study lies in extending the DTG/PC framework to compressible, non-isothermal power-law fluids, which has not been reported in the literature. The method captures the complex thermodynamic-rheological coupling and produces stable, high-fidelity evolution. This gap is addressed by providing a robust numerical infrastructure for simulating complex flows essential to diverse scientific and industrial applications.

2. Mathematical description

The continuity, momentum, and energy equations that govern non-isothermal, compressible, inelastic, flow are expressed in two-dimensional cylindrical coordinates (r, z) respectively, as [34, 35]:

2 2ev ^ + v.d h v l = d ^ 2n s d h - 3 d ^ n s d.v h - dp. 2t

2v r 1 2p 1 2 2 lE ;n b - d $ v + 2 -t + 2r t 2r s 3 2r 2v r 2v z 1 2 1 2 n s 2v r v r l lE + t r b ;n b +t + , 2z s 2z 2r 2r r

2v z 1 2p 1 2 2 lE ;n b - d $ v + 2 -t + 2r t 2z s 3 2z n 2v z 2v r 1 2 1 s 2v r 2v z l lE + t r b ;n b +t + + . 2r s 2r 2z 2z 2r

1 2 2T 2T 2T 2T 2 2T b kr l+ bk l + U. + vr + vz D= r 2t 2r 2z 2r 2t 2z 2z (7)

Where v = ^ v r, v z h, p, t and n s are the velocity vector, pressure, density, and solvent viscosity of the fluid, respectively. In the energy equation, the two variables each represent the temperature T , the heat capacity Cp , the thermal conductivity k, and the dissipation function U . The deformation tensor’s Euler rate is defined as follows. d = (dv + (dv) @)/ 2. The solvent viscosity is calculated using a power-law model, which is defined as [32]: n-1 n s = m ^ c h (8)

Where, m is consistency parameter, n is power-law index and c represent the shear rate of simple shear flow defined as [32]: c = 2 P . (9)

Where, II denotes the second invariants of the rate of strain tensor, which can be articulated in an axisymmetric coordinate system as follows [32]: 1 2v r l2 b 2v z l2 a v 2r k 1 b 2v r 2v z l2 1 II = 2 ' b . + + r +2 + 2r 2z 2r 2z

To non-dimensionalize the conservation (of mass, momentum and energy), we have used the following variables: v = V 0 v *, t = t 0 t *, p = 0

ns V0 * L2 t 0 * T - T0 1 * p , T , d d , t = = = ns t , L L DT 0

where V is the characteristic velocity, p is the characteristic 0 pressure, t 0 is the characteristic density, T is the characteristic temperature, L is the characteristic length, and DT is a difference reference temperature. Using the quantities defined above, Equations 1 through 6 can be transformed into the following equations: Conservation of mass

2 2v ^ + v.d h v l = d ^ 2n s d h - 3 d ^ n s d.v h - dp. 2t

2v r 1 1 2p 1 1 2 2 lE ;n b - d $ v + 2 - t Re + 2r t Re 2r s 3 2r 2v r 2v z 1 1 2 1 1 2 n s 2v r v r l lE + t Re r b ;n b + t Re + , 2z s 2z 2r 2r r

2v z 1 1 2p 1 1 2 2 lE ;n b - d $ v + 2 - t Re + 2z t Re 2z s 3 2z n s 2v r 2v z 2v z 2v r 1 1 2 1 1 lE + t Re r b l. ;n b + t Re + + 2r s 2r 2z 2z 2r

In component form: 2T 2T 2T t Re Pr : + vr + vz D 2t 2r 2z 1 2 2T 2 2T b kr l+ bk l + Pr EcU. = r 2t 2z 2z 2r

Where Re, Pr and Ec are non-dimensional values representing the Reynolds number, Prandtl number, and Eckert number, respectively, defined as [35,37]: t0 V0 L ns , ns Pr = k/C , p (V 0 ) 2 Ec = C p Dt Re =

Then, we need to specify an equation of state — a relation between density and pressure — to close the two governing equations (mass and momentum) outlined above. The modified Tait of state equation has been assumed in the form [38]:

Here A and B represent parameters, and denote p 0, t 0 the reference values of pressure and density, respectively. By rearranging and differentiating Equation 18, we obtain:

2p A (p + B) (19) = Aat A - 1 = = c 2(x,t) t 2t 0 (p + B) Where, a = is constant and c(x,t) is the speed of sound. t A0

3. Numerical algorithm

In this section, we discuss the DTG/PC method, which is used to solve the governing equations for compressible non-Newtonian fluids with thermal effects. The algorithm employs the Taylor-Galerkin technique, a fractional-step method that initially semi-discretizes time using a Taylor series expansion, and subsequently applies a pressure-correction approach. This numerical strategy was first introduced by Hawken et al. [27] to address incompressible isothermal flows. Subsequently, the Lax-Wendroff two-step [39] procedure was applied to the preceding equations and to derive the following results. Momentum conservation equation becomes: step1: v n + 1/2

Dt step2: v n + 1 = v n + t Re ( (v n + 1/2, d n + 1/2) - dp n + 1/2),

In step 2 of Equation 20, we approximate pressure p n + 1/2 by using Crank-Nicolson method as [40]: p n + 1/2 = jp n + 1 + (1 + j) p n

Now using Equation 22 we can re - written step 2 of Equation 20 as: v

Dt = v + t Re ^ (v n + 1/2, d n + 1/2) - jdp n + 1 - (1 - j) dp n h . n

The velocity v* introduce to solve Equation 23 in conjugation with the compressibility Equation 11, as: Dt v * = v n + t Re ^ (v n + 1/2, d n + 1/2) - dp n h .

Now by subtracting Equation 24 from Equation 23 we have jDt v n + 1 = v ) - tRe dq n + 1,

Taking the divergence of both sides of Equation 25 together with using Equation 11 Dt n + 1 + d $ (t Re v )) = jDtd 2 q n + 1 Dt

Moreover, by applying the chain rule to Equation 19 and performing difference operations, the density increment can be expressed in terms of the pressure increment, Dt n + 1 1 Dp = 2 . c (x,t) Dt Dt n+1

Substituting Equation 27 in to Equation 26 we get n+1 1 Dp + d $ (t Re v )) = jDtd 2 q n + 1 . 2 c (x,t) Dt

Dt step2: T n + 1 = T n + t RePr (G (v n + 1/2, T n + 1/2), (29) where,

Thus, from Equation (20 step 1), and Equations 24, 25, 27, 28, 29, we can solve the system of compressible non-Newtonian inelastic equations at the following stages: stage1:

Now, these stages can be described in matrix/vector form as follows: stage1:

2t n Re † 2 MDV n + 1/2 = L P n - SV n + 3 DV n - t n Re N (V n) V n + B, Dt

t n Re † 2 MDV * = L P n - SV n + 1/2 + 3 DV n + 1/2 - t n Re N (V n + 1/2) V n + 1/2 + B, Dt

2t n RePr MDT n + 1/2 = -CT n - t n RePr N (T n) V n + B + Pr EcU, Dt

t n RePr MDT n + 1 = -CT n + 1/2 - t n RePr N (T n + 1/2) V n + 1/2 + B + Pr EcU, Dt

where, DV n + 1/2 = V n + 1/2 - V n, DV n + 1 = V n + 1 - V *, DT n + 1/2 = T n + 1/2 - T n, DT n + 1 = T n + 1 - T n, Dp n + 1 = p n + 1 - p n, Dt n + 1 = t n + 1 - t n and DV ) = V ) - V n .

V, T, ρ, and P represent a velocity, energy, density, and pressure vector, respectively. The vector of pressure difference is defined as Qn+1 = Pn+1 - Pn . The notation and structure of the matrix are delineated as follows:

S ij = GdK i, dK j + (dK j) † H = # n dK i:( dK j + (dK j) †) dX X

D ij = [dK i, dK j] = # n dK i $ dK j dX , K ij = [d} i, d} j] = # d} i $ d} j dX s

H i,j = (} i, } j) = # } } j dX, B ij = (} i, d $ (} j K j)) = # } d $ (} j K j) dX X

N (T) ij = [K i, T $ dK j] = # _ | l K i K j T l $ d i K j dX X

N (V) ij = [K i, V $ dK j] = # _ | l K i K j V l $ d i K j dX X

where B , g are a natural boundary vector and given function. We approximate the values of velocity, pressure, and temperature as

follows: v = | i v (t) K i, T = | i T (t) K i and p = | j } j p . K i and } j represent the quadratic and linear shape function respectively. i

4. Specification of the problem and boundary conditions

We investigate the compressible Poiseuille flow (Ps) through a straight, two-dimensional (2D) axisymmetric channel under non-isothermal conditions. We use a highly refined triangular finite-element mesh with a normal junction-configuration, as shown in Figure 1. The mesh comprises 1679 elements, 960 vertices, and 3840 degrees of freedom.

on temperature. Such studies are performed for individual values ^ n = 0.5 to1.5 h of ^ m = 1, 5, 10, 20 h and, to illustrate the range of flow behaviour under varying thermal and rheological conditions.

5.1. Velocity profile with n and m variation

We analyze the effects of power-law index (n) and consistency parameter (m) on fluid velocity at both inlet and outlet of the channel. Within this range, the power-law index is changed between

0.5. # n # 1.5 with steps of , and everything else is kept constant

(e.g. Pr=m=1). The effect of the variation of on velocity profile at channel entrance is presented in Figure 3. As expected, and confirmed as found above, there is no significant effect. This behavior is result of the impact of the boundary conditions (those in Figure 2).

Figure 1. Structured finite element mesh The boundary conditions necessary to solve the problem are setting as follow: 1. At the channel inlet, a prescribed temperature and a fully developed axial velocity profile corresponding to Poiseuille (Ps) flow are imposed. 2. Along the axisymmetric, we assume no slip boundary condition for velocity. 3. Along the channel wall, we assume constant heat flux 2T for temperature, = q 1 , where q1 is constant. 2r The above details are depicted in Figure 2.

Figure 3. Influence of variation n on velocity at inlet The conduit outlet’s behavior differs markedly and apparently affects local velocity. As shown in Figure 4, for sufficiently large values of the independent variable, the velocity slightly n<1 increases, which resembles shear-thinning behavior. In contrast, increasing the n > 1 value yields a small decrease in velocity, characteristic of shear-thickening behavior.

5. Results and discussions

In the present work, we performed systematic simulations of steady, non-Newtonian thermal flow using the DTG/PC method, an advanced and efficient numerical technique. The main purpose of this study is to investigate the impact of the power-law index (n) and the consistency parameter (m) on flow characteristics and to discuss the effect of the Prandtl number (Pr) and the thermal conductivity (k)

Figure 4. Influence of variation n on velocity at outlet We investigate the effects of varying the consistency coefficient (m) at values of 1, 5, 10, and 20, for both shear-thinning (n=0.5) and shear-thickening (n=1.5) fluids, while keeping all other parameters constant (Re=Pr=1). Figure 5 shows that increasing the consistency

coefficient (m) does not affect the inlet velocity profile. This behavior is a consequence of the dominant influence of the inlet boundary conditions, as illustrated in Figure 2.

Figure 5. Influence of variation m on velocity at inlet At the channel outlet, the effect of varying the consistency coefficient is examined using the results presented in Figure 6. The figure demonstrates that increasing m leads to a pronounced rise in velocity relative to that at the channel inlet. Furthermore, it is observed that the influence of increasing m on velocity is more pronounced for power-law index values, which is n < 1 attributed to the shear-thinning behavior of the fluid. Everything that has been mentioned up until this point is consistent with what was provided in [35, 41].

The influence of the consistency coefficient (m={1,5,10,20}) on pressure and density along the centerline is examined in Figure 8 for power-law index values n=0.5 and n=1.5. As illustrated in the figure, with increasing m both p and ρ also increase in each region. However, this behavior is more pronounced for n > 1 (shear-thickening fluids), since the m dependent behavior on the viscosity scaling ratio dominates in shear-thickening regime compared to shear-thinning one [43].

Figure 6. Influence of variation m on velocity at outlet Figure 7 shows the centerline pressure (p) and density (ρ) profiles for different values of the power-law index (n), illustrating pressure- and density-drop profiles as n and m vary. Here we can see the results of ρ and p distribution for maximum values (n=1.5) These observations are consistent with the known physical behaviour of non-Newtonian fluids. Decreasing n increases the fluid’s viscosity (its resistance to flow). Thus, this results in increased pressure and density at the same flow condition [35, 42].

5.2. The relationship between viscosity and shear rate with n

and m variation Is that the viscosity ( n s ) is directly proportional to the shear rate (γ), as shown in Equation 8. The influence of n on this relationship is shown in Figure 9, which demonstrates three regimes based on the value of n. When the shear rate n < 1 increases the fluid exhibits shear-thinning behavior, meaning that the viscosity decreases. This intriguing phenomenon results from entanglements among polymer chains that form when they are incorporated into the fluid, before they flow together. These entanglements break at higher shear rates, allowing chains to align and molecular mobility to increase, which ultimately reduces viscosity. On the other hand, n > 1 the flu-

id exhibits shear-thickening behavior, in which viscosity increases with shear rate. The fluid behaves as a Newtonian fluid, n=1 with a viscosity that does not vary with the applied shear rate. For additional insights, see [44].

Figure 9. Influence of variationn on relation between viscosity & shear rate The consistency coefficient (m) is one of the key parameters in controlling the interaction between viscosity and shear rate. In particular, its influence scales when n > 1 with m, scaling greatly increases the fluid’s aversion to flow. In the opposite direction, for n < 1 , the intrinsic shear-thinning property of fluid with its viscosity declining along with rising shear rate renders m effect infirm [45]. Figure 10 illustrates this behavior.

Figure 10. Influence of variation m on relation between viscosity & shear rate

5.3. Temperature profiles with n and m variations

Show that, in compressible fluids, the effect of the n on temperature (T) is more robust than that in incompressible fluids. As shown in Figure 11, higher values generate higher temperature; this effect is more pronounced in compressible fluids. This increased sensitivity is due to the more complex interdependence between pressure and temperature in compressible fluids, which leads to large temperature-induced changes in parameters such as viscosity (or, more broadly, rheology). In comparison, the relationship between these quantities becomes an easier expression and has a less signification

impact on fluid physical properties for incompressible fluids as presented in [46].

Figure 11. Comparison of the effect of the variation of n on the temperature in the compressible and incompressible states As with n, the effect of m on temperature exhibits a similar trend, though is most significant in compressible fluids. The reason for this is that in compressible fluids density varies considerably with pressure and temperature variations. Therefore, temperature also has significant effect of the consistency coefficient, which is a measure of fluid’s viscosity. However, for incompressible fluids the density is much less affected by temperature changes leading to a two order of magnitude lower dependence of the consistency coefficient on temperature [47]. Observing Figure 12, an increment of m produces a big jump in temperature which is more noticeable for shear-thickening fluids (n=1.5), harsher values of m means that the viscosity raised. Furthermore, it is noted that the influence of m on temperature is more significant in compressible fluids than incompressible fluids.

Figure 12. Comparison of the effect of the variation of m on the temperature in the compressible and incompressible states

5.4. For temperature profiles with k and Pr variation in

Figure 13. Comparison of the effect of the variation of k on the temperature in the compressible and incompressible states As also is the case for thermal conductivity (k) the Prandtl number (Pr) modifies temperature profiles in a similar manner. As illustrated in Figure 14, a decrease of Pr results in an increase of temperature. In particular, as shown in [35], the effect is more significant and pronounced for n=1.5 in the case of compressible fluids.

Thermal conductivity (k) and the Prandtl number (Pr) are key parameters that have a major impact on temperature distribution and heat transfer characteristics. The current study examines the parameters p and Pr, in the range of 0.6≤k=Pr≤1.4 with 0.2 bark steps of, by fixing the value of m=1. Data were analyzed for two power-law indices (n = 0.5), (n = 1.5): shear-thinning and shear-thickening. The results are then compared with those of the incompressible flow case to investigate the effects of these parameters on changes in the thermal and flow fields. The results from comparing the thermal properties with fluid characteristics under different rheological conditions allow insight into the interaction of those properties. For compressible and incompressible fluids, the effect of k on T is depicted in Figure 13 for two values of the power-law index (n=0.5,n=1.5). From the results, we can see that as k decreases, T tends to increases for compressible fluids especially at n = 1.5, as noted by [35].

Figure 14. Comparison of the effect of the variation of Pr on the temperature in the compressible and incompressible states.

6. Conclusion

Finally, we explore the impact of n and m on shear stress ( x rz ) and normal stress ( x zz ) as shown in Figures 15, 16, and 17. Figure 15 shows that the magnitudes of the shear and normal stresses increase, consistent with the shear-thickening behavior of the fluid. These results are consistent with those reported previously [48-51]. When m varies, Figures 16 and 17 show the effects on n = 0.5 and n = 1.5, respectively. The trend shows that the magnitudes of x rz and x zz increase with m shear-thickening fluids clearly following this pattern. This phenomenon is caused by the increased viscosity for larger values of m (as noted in [43]).

This study successfully extends the developed Taylor-Galerkin/ Pressure-Correction method to simulate compressible, inelastic, non-Newtonian fluid flows under non-isothermal conditions in cylindrical coordinates. This approach accounts for the full coupling of momentum, energy, and mass transport due to compressibility, and provides a direct solution to the energy equation via a twostep Lax-Wendroff scheme. Numerical methods have been shown, through quantitative analyses, to be robust and accurate. At the channel outlet, increasing the power-law index from n=0.5 (shear-thinning) to n=1.5 (shear-thickening) caused a reduction in flow velocity by up to, indicating 10% increased flow resistance. For shear-thickening fluids, increasing the consistency coefficient led m=1 to m=20 an 35% increase in outlet velocity, while shear-thinning flows showed 10% a smaller increase due to lower viscosity sensitivity. Pressure (p) and density (ρ) profiles at the pipe centerline showed a peak pressure of approximately 400 and 4 at n=1.5 and m=20 for shear-thickening fluids, indicating that both parameters are strongly related to flow resistance. Likewise, shear and normal stresses increased by as much as 50% with increasing n and m, highlighting their effect on the fluid stress state. Thermal findings demonstrate that, particularly in compressible flows, the temperature increases 20% as the Prandtl number and thermal conductivity decrease. The temperature at the channel outlet T=180 was higher in shear-thickening m=20 fluids, demonstrating the strong coupling between viscosity and thermal diffusion. The novelty of this work lies in extending the capabilities of the Taylor-Galerkin/Pressure-Correction scheme developed for power-law fluids to include compressibility and non-isothermal effects, which have not previously been addressed in this context. It is suitable for simulating realistic industrial processes involving polymer melts, geophysical flows, or high-speed thermally driven systems. Possible future work includes extending the framework to three-dimensional domains, transient flow regimes, and viscoelastic fluid models. Further development of tailored turbulence models and aggressive mesh adaptation strategies will improve simulation fidelity for a range of engineering applications.

Copyright permission statement All figures included in this manuscript are original works created by the authors. No copyrighted figures, images, or graphical elements from other sources have been used in this manuscript.

Nomenclature

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Al-Haboobi, A.; Al-Zaidi, S.H. Computation of compressible non-isothermal power-law model developed Taylor-Galerkin Pressure-corre. Journal of Thermal Engineering 2026, Vol. 12, pp. 1337-1349. https://doi.org/10.47481/jten.0033

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Published1 January 2026
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